TVS/Sundaram Fasteners Socket Head Cap Screws
Grade 12.9 alloy steel socket head cap screws — popularly called Allen bolts — in metric and inch series, from TVS/Sundaram Fasteners, Unbrako, LPS and local makes.
About our socket head cap screws range
Socket head cap screws are our core range. As an authorized TVS/Sundaram Fasteners stockist since decades, Perfect Engineering Co carries TVS/Sundaram Fasteners socket head cap screws to DIN 912, ISO 4762 and IS 2269 in diameters from M3 to M36, with lengths from 6 mm to 300 mm, along with inch sizes to ANSI B18.3 and BS 2470.
We also stock Unbrako and LPS socket head cap screws for applications that call for a specific make, and stainless steel A2-70 / A4-70 cap screws for corrosive environments. Large-diameter Allen cap screws and non-standard lengths can be sourced on request.
Common sizes we supply: M4, M5, M6, M8, M10, M12, M16 and M20 allen bolts — for example M6 x 20, M8 x 30, M10 x 40, M12 x 50, M16 x 60 and M20 x 80 — in grade 12.9, plus inch allen bolts from 1/4" to 1".
Also known in the trade as: Allen bolt, Allen screw, Allen cap screw, Allen key bolt, SHCS, Socket screw, 12.9 allen bolt, SS allen bolt.
Available makes
Technical specifications
- Material
- Alloy steel · Stainless steel SS 304 / 316
- Grade / Property Class
- 12.9, 10.9 · Stainless A2-70, A4-70
- Standards
- DIN 912 · ISO 4762 · IS 2269 · Inch: ANSI B18.3, BS 2470
- Diameter
- Metric M3 – M36 · Inch 1/8" – 1-1/2"
- Length
- 6 mm – 300 mm · Inch 1/4" – 12"
- Thread
- Metric coarse · Fine pitch, BSW, UNC, UNF on request
Finishes available
Black Oxide / Self Colour
Standard heat-treated finish with light oil. Default for high-tensile grades 8.8–12.9.
Zinc Plated – White / Clear
Bright silver electroplate for indoor corrosion protection.
Zinc Plated – Yellow
Yellow-passivated zinc with better salt-spray life than clear zinc.
Zinc Flake (Geomet / Dacromet)
Non-electrolytic coating with high corrosion resistance and no hydrogen embrittlement — preferred for 10.9 & 12.9.
Stainless Steel SS 304 (A2)
Natural finish; general corrosion resistance for food, pharma, and outdoor use.
Stainless Steel SS 316 (A4)
Molybdenum grade for marine, chemical, and coastal environments.
Socket head cap screw size chart (DIN 912 / ISO 4762)
| Size | Pitch (mm) | Head Dia (mm) | Head Height (mm) | Allen Key (mm) | Typical Lengths |
|---|---|---|---|---|---|
| M3 | 0.5 | 5.5 | 3 | 2.5 | 6 – 40 mm |
| M4 | 0.7 | 7 | 4 | 3 | 6 – 50 mm |
| M5 | 0.8 | 8.5 | 5 | 4 | 8 – 80 mm |
| M6 | 1.0 | 10 | 6 | 5 | 8 – 100 mm |
| M8 | 1.25 | 13 | 8 | 6 | 10 – 150 mm |
| M10 | 1.5 | 16 | 10 | 8 | 12 – 200 mm |
| M12 | 1.75 | 18 | 12 | 10 | 16 – 200 mm |
| M14 | 2.0 | 21 | 14 | 12 | 20 – 200 mm |
| M16 | 2.0 | 24 | 16 | 14 | 20 – 250 mm |
| M20 | 2.5 | 30 | 20 | 17 | 30 – 300 mm |
| M24 | 3.0 | 36 | 24 | 19 | 40 – 300 mm |
| M30 | 3.5 | 45 | 30 | 22 | 50 – 300 mm |
| M36 | 4.0 | 54 | 36 | 27 | 60 – 300 mm |
Lengths listed are typical ranges. Inch sizes (BSW / UNC) available — ask for the inch chart.
Common questions
Is an Allen bolt the same as a socket head cap screw?
Yes. 'Allen bolt' is the common Indian trade name for a socket head cap screw — a cylindrical-head screw driven by a hex (Allen) key.
What does Grade 12.9 mean?
12.9 means a minimum tensile strength of 1200 MPa and a yield strength of 90% of that. It is the standard grade for TVS/Sundaram Fasteners and Unbrako alloy steel socket screws.
TVS/Sundaram Fasteners or Unbrako — which should I buy?
Both are premium Indian makes. TVS/Sundaram Fasteners is usually the more economical choice for OEM volumes; Unbrako is often specified by name in drawings. We stock both, so you can compare prices before ordering.
Can I order stainless steel socket head cap screws?
Yes, in SS 304 (A2-70) and SS 316 (A4-70), from M3 upward.
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